In binoculars with an integrated rangefinder, the following has to be integrated in the optical systems and bodies: a transmission channel for the measurement signals from the measurement signal transmitter, a detection channel for the measurement signals to the detector, and a display channel(s) of the reticle and detection results. The rangefinder is integrated into the binocular by means of a variety of designs.
The known solutions, despite different structure and scope of patent claims, address the effective irradiation of the measured object and the detection of the reflected signal of the transmitted infrared radiation in a specific manner; some solutions also focus on the reticle and measurement data integration into the optical system of the binocular. Apart from gaining the maximum efficiency of the channels, it is the minimisation of the parallax between the channels and the maximum precision of target acquisition for all measurement distances that play a key role. Design, user friendliness and accessibility of gauging elements also apply.
For example, in patent application EP 1 542 052 A1 “Binokulares Ferglas mit integriertem Laser-Entfernugsmesser”, the transmission channel is located in the axis of the hinge bridge connecting the two tubes but the transmitter housing is mechanically attached to the tube which integrates the detection channel of the measurement signals of the receiver. The display channel of the reticle and measurement results is also integrated in this tube. Both the detection and display channels are connected with the observation optical system of the same tube. In this arrangement, the parallax between the detection and display channels is avoided; however, the parallax occurs between the transmitter, which is located in the central axis of the binocular and the other two channels located in the tube of one of the observation channels.
The subject of patent application EP2 078 975 A1 “Binokulares Fernglas mit Entfernugsmesser” addresses only two modules: the transmission channel of the measurement signals of the transmitter, which is integrated into the radial path of the optical system of the first tube of the binocular, and the detection channel, which is integrated into the beam path of the optical system of the second tube of binocular. Embodiments of invention do not address the integration of the reticle display and measurement results. The principle of the transmission beam integration and the detection beam separation according to the patent is fully functional; however, dividing both the prisms with a cement layer, which may adversely affect the quality of one or the other observation channel, may be considered a disadvantage. Embodiments of the invention do not address the integration of the display beam displaying the reticle and the measured values. In this arrangement, the integration can result in a lower permeability of one of the two observation channels. The parallax between the transmission and detection channel resulting from the spacing of the observation systems of the binocular has to be taken into account.
More options are defined in patent application EP 2 378 245 A1 “Beobachtungsgerät mit Entfernugsmesser”: in the main claim, the transmission channel is connected with the observation system of the first tube, and the detection channel is integrated into the observation system of the second tube. Connection of the transmission and detection channel with the same observation optical system is also described; the reticle display channel can also be integrated in the same optical system while the display channel of the measurement results is integrated into the optical observation system of the second tube of the binocular. There is an option to join the channels of the reticle and measurement results of the reticle integration and to integrate them into the optical system of the second tube of the binocular. Considering the minimisation of the parallax between the transmission channel, detection channel and reticle, the best option is to integrate all the three channels so they have a common optical axis at the output or input of the binocular. This can only be achieved by the integration into a single observation system of the binocular. One of the options of embodiments of the invention according to EP 2 378 245 A1 offers such a solution. A certain disadvantage of this solution can be the use of an infrared radiation beam splitter for the path of the transmitter optical system to reflect and the path of the detector optical system to pass, which reduces the effectiveness of the measurement signal detection. In principle, the same applies to solutions with splitters using semi-permeable layers and solutions using surface aperture division to reflective and permeable parts, which is also mentioned.
A specific design of the detection channel integration into a single observation system shown in patent application EP 1 069 442 A2 is an example where reflecting and separating the signal at reflective layers significantly weakens the brightness of the display image.